[asterisk-bugs] [Zaptel 0011855]: REGRESSION: DTMF generation problem

[noreply at bugs.digium.com]

A NOTE has been added to this issue. 
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http://bugs.digium.com/view.php?id=11855 
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Reported By:                meneault
Assigned To:                sruffell
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Project:                    Zaptel
Issue ID:                   11855
Category:                   zaptel (the module)
Reproducibility:            always
Severity:                   major
Priority:                   normal
Status:                     acknowledged
Zaptel Version:              SVN 
SVN Branch (only for SVN checkouts, not tarball releases):  1.4  
SVN Revision (number only!): 3490 
Disclaimer on File?:        N/A 
Request Review:              
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Date Submitted:             01-28-2008 01:06 CST
Last Modified:              02-23-2008 04:04 CST
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Summary:                    REGRESSION: DTMF generation problem
Description: 
Zaptel don't send DTMF tones correctly on FXO lines. For instance when
trying to dial out a number.
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---------------------------------------------------------------------- 
 meneault - 02-23-08 04:04  
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Hello Everyone,

As I saw much people was experiencing the issue I decided to come back
here to solve it!
Saw I added a lot of print traces, I compared new generated dtmf tables
with the old ones and I must admit that everything is correct in 1.4.8!

The issue is much more subtle than I initially thought, the revision 3490
changes the way zones are loaded in zaptel. So it implicitly changes how
ztcfg utility should talk to zaptel when loading configuration.

And that's the point: when we updated our zaptel version we didn't update
our ztcfg utility!!!!

This is a user-side bug not a code bug! So there is no patch to develop.

Everyone experiencing the issue should only compile ztcfg along with
zaptel and install it too!

I apologize for falling into this trap but actually I was not alone...


And there is something to learn from this:

- when we are using an incompatible user-space application with zaptel it
does not always fail.
In this case neither ztcfg, neither zaptel-base is aware that something is
 going wrong. Using an older ztcfg just work but the dtmf tones and mf
tones are just not initialized at all. And zaptel successfully prints out
"Zone Loaded..."


- My personal advice on this is to add some kind of user-space API version
checking.
One possible solution is to add a new ioctl ZT_USERSPACE_API returning the
current user-space API version.
This API version number should be hardcoded in zaptel.h.
The API version number should be changed anytime there is a change in
user-space to zaptel communication (mainly ioctls changes).
Then when an user-space application wants to talk with zaptel before any
other ioctl it should call ZT_USERSPACE_API to be sure that it can talk to
zaptel safely.
It would avoid that strange bugs which are really hard to solve!


I apologize again for having messed up everyone with wrong clues and for
not having solved it before but I was really busy! 

Issue History 
Date Modified   Username       Field                    Change               
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02-23-08 04:04  meneault       Note Added: 0082800                          
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